There is also a session at the Anvil in Bonnyrigg on the Friday night, which is oriented more towards singing with guitars and so might be more your sort of thing than Bell's. 8.30pm - midnight. Bonnyrigg is easy to get to (no.31 bus or N31 night bus from the city centre).

I don't think I'll go back for a while, as the last time I was there there was only one other melody player confident enough to start a tune and no less than NINE guitars.